Date   : Wed, 29 Aug 2007 14:07:05 +0100
From   : pete@... (Pete Turnbull)
Subject: Econet oddities

On 29/08/2007 12:58, Rob wrote:
> On 29/08/2007, Chris Priest <chris.priest@...> wrote:
> 

> It sounds like you've done your best, but it is almost certainly the
> wrong cable; econet uses a differential signal like ethernet 10baseT
> rather than a signal-to-ground like RS232/432 seral.  For this to work
> reliably at speed, the cables in the pair are supposed to be twisted
> together, and always kept the same length.

Yes, except there's supposed to be a common ground too.  It's supposed 
to be shielded but you can often get away with using something like Cat5 
cable if you use one or two spare wires as ground.

>> The cable is shielded, the shield being used as earth.
> 
> Make sure you only connect shields at *one* end to avoid creating hum
> loops ...

No, the spec requires the ground to be connected at each socket.

-- 

Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York